The use of chalcogenide compounds for fabricating antireflection coatings in the mid-IR region

This paper describes a method for synthesizing antireflection coatings. The method is based on the optimization of a stepwise coating in terms of the refractive index of layers consisting of quarter-wave films, followed by replacement of the layers with three-layer equivalent structures. The method makes it possible to find practicable structures of antireflection coatings that decrease reflection in the wavelength ranges from lambda(0)-2 lambda(0) to lambda(0)-6 lambda(0). Chalcogenides and fluorides are used as film materials. The optical constants of these substances are studied by a spectrophotometric method. (C) 1997 The Optical Society of America.